1. Field of the Invention
This invention relates to a polyurethane-based friable sealing compound produced from a polyol component and an isocyanate component.
In many fields of industry, a housing, a tube or similar articles have to be sealed at their open end(s) so that moisture or water is unable to penetrate. This applies in particular to cables for the transmission of information, for example in the communications field and in various parts of the electrical industry.
2. Discussion of Related Art
Communications cables consist of a plurality of electrically conductive wires which are bunched together, several such bunches being, accommodated in an outer protective sheath. To join two such cables or even to join cables of different construction to one another, these bunches of wires have tn be fanned out and joined to the wires of the other cable. The individual wires thus joined have to be insulated from one another, so that, in some cases, a much more bulky structure is formed. Since the insulation of the individual wires was opened, this structure has to be protected against the penetration of moisture or water. This is done by so-called cable fittings in the form of connectors consisting of a joint box and a plastics material accommodated therein, this plastics material being known as a friable sealing compound because it is required to show high notch sensitivity. Friable sealing compounds can be removed easily by hand without any need for special tools. They must have a high volume resistance, for example where they are used in cable fittings, and in addition their so-called pot life during processing should be long but, if necessary, should be able to be shortened by addition of catalysts.
In view of the efforts being made to replace petrochemical products by renewable raw materials, it would be desirable if friable sealing compounds could be provided on the same basis. Finally, a friable sealing compound should as far as possible be a homogeneous product, i.e. a uniform product with no additives.